BARBARA F. WALTER is Professor of Political Science at the University of California–San Diego’s School of Global Policy and Strategy.

Since October, the Islamic State (or ISIS) has appeared to be on the verge of defeat. Yet even if ISIS were never to reemerge, the United States is no more secure against the jihadist threat than it was in the past. ISIS is just one of hundreds of Islamist extremist groups that have formed since 2011. All of these groups have similar goals centered around creating a transnational caliphate using military force, and all of them see the United States as standing in their way. In the event of ISIS’ defeat, numerous additional Salafi jihadist organizations will be ready to take its place as long as the conditions that gave rise to the group persist.

One of the major trends[1] over the last six years has been the rise of Islamist extremist groups fighting in civil wars in Muslim-majority countries. By 2016, Salafi jihadist groups made up approximately 35 percent of all major militant groups in Iraq, 50 percent of major militant groups in Somalia, and 70 percent of the groups in Syria.

The primary reason for this rise in jihadist organizations is the sharp increase in the number of civil wars in Muslim countries since 2001. Historically, civil wars[2] have proven to be a breeding ground for this type of extremism. In fact, as long as the current conflicts continue in Chad, Iraq, Libya, Mali, Nigeria, Pakistan, Somalia, and Syria, the Islamist insurgents that have emerged in these wars will also endure.

Civil wars create weakened or failing states—gray zones—where nonstate actors can operate and build their support. This is exactly the environment in which many of the world’s worst terrorist groups, including Hamas, al Qaeda, and ISIS, first began to thrive. Today, the main threat from al Qaeda and its franchises stems entirely from ungoverned states experiencing violence and instability. Extremist groups’ efforts to gain traction in more stable countries such as Egypt, Jordan, Morocco, and Saudi Arabia continue to fail.